From b79e99bfb4bcc7694401cd94a1bb14faee8af048 Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Fri, 13 Oct 2017 11:58:21 -0700 Subject: [PATCH] runtime: remove commented out code from ARM Linux boot The code was commented out by https://golang.org/cl/13234050 in 2013. Let's just remove it. Change-Id: I46ae1f07386719e991458e782d236214c40bdce1 Reviewed-on: https://go-review.googlesource.com/70770 Run-TryBot: Ian Lance Taylor TryBot-Result: Gobot Gobot Reviewed-by: Austin Clements --- src/runtime/rt0_linux_arm.s | 60 ++----------------------------------- 1 file changed, 2 insertions(+), 58 deletions(-) diff --git a/src/runtime/rt0_linux_arm.s b/src/runtime/rt0_linux_arm.s index 597e642adb..b56ec75071 100644 --- a/src/runtime/rt0_linux_arm.s +++ b/src/runtime/rt0_linux_arm.s @@ -93,76 +93,20 @@ GLOBL _rt0_arm_linux_lib_argv<>(SB),NOPTR,$4 TEXT _rt0_arm_linux1(SB),NOSPLIT,$-4 // We first need to detect the kernel ABI, and warn the user - // if the system only supports OABI + // if the system only supports OABI. // The strategy here is to call some EABI syscall to see if // SIGILL is received. - // To catch SIGILL, we have to first setup sigaction, this is - // a chicken-and-egg problem, because we can't do syscall if - // we don't know the kernel ABI... Oh, not really, we can do - // syscall in Thumb mode. + // If you get a SIGILL here, you have the wrong kernel. // Save argc and argv MOVM.DB.W [R0-R1], (R13) - // Thumb mode OABI check disabled because there are some - // EABI systems that do not support Thumb execution. - // We can run on them except for this check! - - // // set up sa_handler - // MOVW $bad_abi<>(SB), R0 // sa_handler - // MOVW $0, R1 // sa_flags - // MOVW $0, R2 // sa_restorer - // MOVW $0, R3 // sa_mask - // MOVM.DB.W [R0-R3], (R13) - // MOVW $4, R0 // SIGILL - // MOVW R13, R1 // sa - // SUB $16, R13 - // MOVW R13, R2 // old_sa - // MOVW $8, R3 // c - // MOVW $174, R7 // sys_sigaction - // BL oabi_syscall<>(SB) - // do an EABI syscall MOVW $20, R7 // sys_getpid SWI $0 // this will trigger SIGILL on OABI systems - // MOVW $4, R0 // SIGILL - // MOVW R13, R1 // sa - // MOVW $0, R2 // old_sa - // MOVW $8, R3 // c - // MOVW $174, R7 // sys_sigaction - // SWI $0 // restore signal handler - // ADD $32, R13 - B runtime·rt0_go(SB) -TEXT bad_abi<>(SB),NOSPLIT,$-4 - // give diagnosis and exit - MOVW $2, R0 // stderr - MOVW $bad_abi_msg(SB), R1 // data - MOVW $45, R2 // len - MOVW $4, R7 // sys_write - BL oabi_syscall<>(SB) - MOVW $1, R0 - MOVW $1, R7 // sys_exit - BL oabi_syscall<>(SB) - B 0(PC) - -DATA bad_abi_msg+0x00(SB)/8, $"This pro" -DATA bad_abi_msg+0x08(SB)/8, $"gram can" -DATA bad_abi_msg+0x10(SB)/8, $" only be" -DATA bad_abi_msg+0x18(SB)/8, $" run on " -DATA bad_abi_msg+0x20(SB)/8, $"EABI ker" -DATA bad_abi_msg+0x28(SB)/4, $"nels" -DATA bad_abi_msg+0x2c(SB)/1, $0xa -GLOBL bad_abi_msg(SB), RODATA, $45 - -TEXT oabi_syscall<>(SB),NOSPLIT,$-4 - ADD $1, R15, R4 // R15 is hardware PC - WORD $0xe12fff14 //BX (R4) // enter thumb mode - // TODO(minux): only supports little-endian CPUs - WORD $0x4770df01 // swi $1; bx lr - TEXT main(SB),NOSPLIT,$-4 MOVW $_rt0_arm_linux1(SB), R4 B (R4)